Permanent mold



March 18, 1924.

M. F. HILL PERMANENT MOLD Original Filed Feb. 28, 1918 2 Sheets-Sheet 1 iv vh 3 We Po mm 5N RN N hNivN MN March 18, 1924.

NL F. HILL.

PERMANENT MOLD Original Filed Feb. 28. 1918 2 Sheets-Sheet 2 ATTORNEYS.

Patented Mar. 18,- 1924.

OFFICE.

MYRON HILL, OF NEW YORK, N. Y.

PERMANENT MOLD.

Application filed. February 28, 1918, Serial No. 219,562. Renewed March 29, 1921. Serial No. 456,693.

To all whom it may concern: I

Be it known that I, MYRoN F. HILL, a citizen of the United States, residing at New York city, county and State of New York, have invented certain new and useful Improvements in Permanent Molds, of which the following is a specification, reference being had therein to the accompanying drawings, forming part thereof.

My invention relates to apparatus and methods for casting, particularly for casting steel, and more particularly for casting steel ships in sections.

One of the objects of my invention is a form of permanent mold made of low heat conducting material having a high fusing point, above that of steel at the temperature of pouring, and so surfaced or prepared that molten metal will not adhere thereto. v

Another object of my invention is a mold formed of such materials having open spaces for casting the ribs and shell of a ship and provided further with collapsible members to allow free shrinkage of the casting without injuring or destroying the mold or the casting.

A further object of my invention is a mold adapted to be opened with ease in order to remove the casting quickly at the proper temperature, and also in order that the mold may be ready for another pouring.

A further object of my invention is to reduce the severity of action of molten steel upon the surface of the mold by heating the mold and preferably keeping it hot'during its time of continuous service in forming the castings.

In the drawings:

Figure 1 is a section of Figure 3 upon the line 11, showing a modification in the right portion at 66 and 67.

Figure 2 is an enlarged view of the left hand end of Figure 3, taken upon the line 22 of Figure 1.

Figure 3 is a section of a portion of Figure 1 upon the line 33.

Figure 4 is a detail.

Figure 5 is a vertical elevation of the mold ready for pouring.

Figures 6 and 7 show the forms of fire brick and the holders thereof for the sides of the mold, Figure 6 being the form for the far side of the mold shown in Figure 5, and Figure 7 for the near side thereon.

In Figure 5 is shown a shaft 8, adapted to be mounted upon any suitably fixed base 9 or to be swung in 'a-hook 10 carried by a crane. Upon the shaft 8 are pivoted jaws 11 and 12, the jaw llsecured to the bed 13 of the mold and the jaw 12 secured to the end casting 14 of the mold. The end casting is provided with fire bricks 15 and 16 held between the dove-tailing angles 17 and the separate dove-tailing forms 18 and 19. This end casting is also provided with fire bricks 20 found in place by the plate 21. The bearing in 12 is loose in a direction at right angles to the general plane of the mold.

These fire bricks, as is the case with all fire bricks intended to be used in the mold having surfaces presented to the molten steel, are prepared of material having a surface fuslng point well above that of molten steel. Fire brick, for example, having a surface fusing point of 3100 F. is well adapted for this purpose. The fire brick is made in molds with surfaces as smooth as or more adjoining bricks, so that they form a solid bed. In this form, the surface of the fire brick that is presented to the molten steel may be baked by directing thereupon suitable heat, such for example as from any suitable gas or oil burner, until the hinder or filler between the bricks near the surface of the mold has become suitably baked. Thereafter graphite may be painted or rubbed on to prevent the adhesion of steel, the graphite filling all the pores of the brick and being smeared over the smooth surface. This graphic surface may or may. not. be baked into the mold by the application of heat, as above outlined. These bricks may also have a further treatment during their process of manufacture. which the bricks are formed graphite or carborundum or any suitable material having a high fusing point and preferably containing a suitable binder such as is used in fire brick for example, and capable of receiving a surface adapted to prevent the adhesion of steel thereto, may first be deposited and the rest of the molds filled with are In the molds in.

brick clay. After being formed these bricks may be removed and baked separately in an oven and then assembled in a mold, the crevices in the bricks being treated as above, that is, by employing a filler between the bricks and covering the filler at the surface with a suitable graphite or other substance that has a highfuslng point and is not adhesive to steel during the formation of castin Th Figure 1 the fire bricks are. shown providing the space 22 for the shell of a cast section ofa ship and the space 23 for the rib of such a section, as for example, the socalled longitudinal, well known in the Tsherwood system of shi construction. Three sets of bricks are use on one side of this casting, illustrated at 24, 25 and 26. The bricks 24 and 25 are mounted upon a frame or form 27 and held in place by a clamp 28 and screw threaded posts and nuts 29 through brackets formed upon the member 27. The fire bricks 26 are held between the frame members 31 and '32, which are bolted together, as illustrated at 33. Each of the members 32 is l..-shaped; the other portion of the IL. being represented at '34, carrying end bricks 35, as shown in Figure 2, forming one side of a right-angled rib 36, which may, for example, be the so-called transverse, well known in the Tsherwood system. Obviously the mold thus described is adapted to form a side section of an Isherwood type ship.

The longitudinal rib portions of the casting are provided with bulb portions, illustrated at 37, and with stringer portions 38. The stringer portions 38 and the longitudinal portion 23 during contraction of the casting approach each other and in order to allow this action without injuring the casting the various members 3234 slide upon each other at the dividing lines 39, so that while the members 27 remain in their normal positions, the members 3234 are pushed out of position by the force of contraction of thecasting. This collapsing action is resisted by springs 40 between the abutments 41 upon the members 31 and the abutments 42 upon the bed 13. The abutments 42 pass through the member 32 in the slots 43, which are sufiiciently large to permit all the various motions of the members 32 and 13 with relation to each other. The top of the abutment 42 is provided with a surface 44 upon which rests the member 27. This member 27 is adapted to slide upon the member 31 and if necessary upon the'inclined surface 44 of the abutment 42. Rollers 45 between the members 27 and 31 may be provided if desired to render the sliding action more free and frictionless. The portions 34 also are provided with rolling bearings, as indicated at 46, eachlconsisting of a housing 47, illustrated also in Figure 2-, secured to the members 34 and adapted to carry rollers 48, rolling u on ledges 49, which may also be e .1..- ployed to form the dove-tailing portions to hold the bricks 35 in place. The end frame 14 is also bolted to a cover 50, which is in. the form of a grid having perforations 531 to allow-of the insertion of clamps 52, which. are adapted to be secured to ribs 53 (Fig. thereby securing the bricks 54 in place. When the two parts of the, mold are closed on each other suitable spacers of metal er fire brick for lighting holes may be employed to establish the thickness of the shell of the casting. The mold is'held properly closed by any suitable pressure.

To protect the collapsing mechanism of the mold from splashing metal, an end gate bar 55 is formed of bricks dove-tailed in suitable frame bars 56. The bars may be united by end straps shown in broken lines 56 (Fig. 5) and are provided with loops 57 for the purpose of handling. The gate bar is adapted to fit over the end of the mold and protect it during curing. This end bar is provided with suita le funnel openings 58 adapted to receive and direct the metal into the bulb channels 37 for the various longitudinals and corresponding portions of the stringer 38 and any other stringer that may be desired, an open space 59 being left between the bar and the end of the mold to permit the overflow of metal from the mold. "When the overflow occurs the pouring is stopped and the end bar 55 is removed; some non-conductor of heat being thrown over the end of the mold to delay the cooling of the metal in the channels 37 if desired. As the metal at the top is poured last and is hottest, naturally it will cool last. The channels 37 being subjected to a stream of metal will also cool more slowly than other portions. The metal that reaches the shell portion 22 of the mold, particularly where the streams of metal meet between the longitudinals etc., will cool first and particularly the metal in the space 36 which, being the first portion of the mold to fill up will cool first.

In order to permit the metal in the bulb space 60 to shrink towards the shell portion 22 of the casting, the bricks 61 held in a dove-tailing metal frame 62 and having the cam-shaped faces 63 are pushed backward by the bulb portion of the casting against the resiliency of the springs 64, of which there should be a suitable number, the other ends of the springs resting against the frame portions 14 ofthe mold.

In order to expedite the cooling of the bulb portion of the casting a rod 65 may be inserted in the mold, which should be of such size as to be heated to a temperature above the welding point, so that it will become an integral part of the bulb. This rod, however, may be omitted and the roximity of this bulb to cooling metal be re ied upon until after the transverse portion of the cast- 1 ing 36 has reached that stage, the transverse portion 36, due to contraction, frees itself from the surface of the forming bricks, thereby allowing the members 32 and 34 to slide freely.

The dividing lines between the bricks 25 and 26 may be protected by metal, as shown at 66 and 67 (Fig. 1) if desired, the metal. of these brick holding portions of the mold being brought to the surface, where they may be in contact with the molten metal. In such case the surface of the frame members of the mold presented to molten steel should be smooth and covered with graphite for each pouring. As this metal will cause the liquid steel to freeze at this point sooner than at other portions of the mold the amount of frame metal exposed to the mo!- ten steel should be so small as not to crystallize the casting. In other words, the rate at which the heat travels from the molten metal into the metal frames should be less than the travel of the heat th'rough the cast metal itself, so that when the casting is removed from the mold it will still be at an annealing temperature.

Then the metal has frozen sufiiciently to provide strength in the casting, such that the casting may be handled and lifted out of the mold, the operator may rotate the rod 68 in its bearings 69, upon the bed 13 of the mold, thereby swinging the arms 70, the yoke ends of which 71 engage the grooved ends of the rods 72 (see also Figure 1) thereby oscillatin the levers 73 upon the pivots 74 journal ed in the bed frame so that the other ends of the levers 75, through obvious pin and slot connections, are adapt.- ed to pull upon the rods 76, swiveled at 77 in the members 31, thereby withdrawing them to such an extent that the casting may be removed without the bulbs 37 catching in the mold.

When the mold is opened the abutments 42 carry with them the members 32; also the members 27, together with the bricks 24 and 25, which is brought about by the clips 79 (Fig. 4), secured to studs 80, formed upon the abutments and passing through slots 8% in the ribs 82 (Fig. 1) of the members 2 In Figure 7 the frame member 83 is provided with an extension 84:, adapted to support the peculiar form of brick 85.

In pouring, the mold may be tipped at any suitable angle, if desired, as for exmold may rest, allowing the mold to be opened, as above described.

The angle at which the mold is inclined for pouring should. be adjusted to such a point that the liquid metal flows freely down the bulb channels 37 without forming open spaces between the portions of metal which might thereby create blow holes in the casting. The metal should run smoothly and in solid and dense streams throughout the mold and the an le at which the mold is inclined should be a j usted to secure this result. As the surfaces are lubricated with non-adhesive coating, the metal'runs freely green sand thinner castings may be poured than is customary with green sand.

The various parts of the mold are supplied with suitable appliances by which they may be handled by cranes to perform these various operations.

4 The metal is prevented from running out of the molds at the sides by forms of bricks, as shown in Figures 6 and 7, the surfaces 77 7 7 a and 7 8 resting against the top bricks 54 at the sides of the mold respectively.

When it is desired to cast] the bottom of sections of ships, the bulb 60 is omitted, as there is no bulb on the top of a floor of the bottom transverse. In such case the mold usually assumes a length of about half of that shown and the depth of the transverse space 36 considerably greater than that shown in this figure.

The thickness of the bricks at the various portions of the molds may be so adjusted as to assist the cooling processes in the stages above described and all the frame members should be given suflicient clearance for interrelated movements as to permit such collapsing action as may be necessary while the casting is freezing and reaching the temperature at which it is removed from the mold.

It has been found possible with green sand to cast sheets-of metal as low as ninesixteenths of an inch in considerable areas.

In casting the sectionsof a ship say, 6f ten thousand tons dead weight capacity many parts of the ship may be as thin as 40% inches in thickness. With a mold having low heat conductivity, the metal has a better chance of becoming distributed through the various parts of the molds and the various streams integrally unite than is possible with green sand. The result of this system of molding is that thinner ship sections -may be cast to accommodate the scantlinfs of a shi havin for exam lo the sh i p than would otherwise be the case.

rthermore with green sand molding the low, limit oi tonnage at which ships may be cast might well be eight to ten thousand tons without increasin the total weight of the steel in the hull, wereas, with my system of molding smaller ships may be cast with the same result. in other words, this system of permanent molds having low heat conductivity allows the casting of ships that it a cold not be profitable to cast with the green sand system, except for emergency purposes.

in designing a ship for casting, from fifteen to twenty per cent oi metal heretofore used for connecting sheets of metal together to form the various members oi the ship may be transferred to the cast portions of the ship to thicken them suiliciently to bring them within the range of casting. l/V hen the casting process permits the casting of a ship with the theoretically correct scantling without increasing the parts for casting purposes, a saving in Wei ht of the steel in the hull may reach the said fifteen to twenty percent.

This saving makes possible either the carrying of additional cargo, or results in a lessor draft for the ship, permitting greater speed or saving in power for propellin the ship. lln this way factors which of t emselves appear to be of slight conmquencc,

have far reaching consequences.

lin casting ship sections for the bow and stern portions for certain forms of ships, the same castings may be utilized provided that the shell portions are cut 0d to fit certain dimensions of the ships. Such sections may be tapered and fitted together, roughly speaking, like the pieces of a pie.

lln order to utilize the hereinbefore described mold of my invention to secure sections of this form and to form lighting spaces, portions of the mold are filled up with some form of filler, either metal or of baked fire brick clay, to shut 0d the access of the metal. Care should be taken, however, not to block the pouring channels through which the metal is poured, except where those channels are not necessary for the result, in which case they may be blocked. ln pouring, one or more ladles may be employed and with spouts registering with the funnel-shaped holes in the pouring bar and metal may be poured into all of the bulb channels, or as manyof them as may bodesired for the casting, simultaneously thereby permitting rapid flowing of the metal and preventing any one stream'of metal from flowing so far as to cool below the point at which it will unite. with another stream which it may meet.

While I have described my invention in entor practice, I would not have it understood that my invention is limited to the forms and details hereinfshown and described, but is pable of widevariations to suit the various needs of the various forms of castings, which it may be desired to produce.

. What ll claim is:

l. A mold having a fire brick linim consisting of bricks dove-tailed in metal. i orms, and having said lire brick mold surface rendered non-adhesive to molten metal.

2. The combination claimed in claim having said mold formed of two parts pivoted for opening and closing.

3. In a mold, metal frame members c0n taining refractory lining having molding surfaces rendered non-adhesive to molten steel, said mold having rib-forming cavities for the casting and containing collapsible members to allow for contraction between said rib members.

42. The combination claimed in claim 3 having said collapsible members sliding upon each other. i

5. The combination claimed in claim ihaving said sliding parts resiliently held together.

6. The combination claimed in claim 5 having rib-forming cavities in said casting at right angles to each other, and sliding parts to' accommodate the contraction between any of said ribs toward each other.

7. The combination claimed in claim 3 having a space to provide a stiffening and strengthening member for the edge of said rib and yielding cam-shaped members to allow for the contraction of said bulb portions towards the main portion of said casting.

8. In a permanent mold for casting sheet of metal provided with ribs, a series of two sliding members between each two ribs, one member adapted to remain in post tion as the casting contracts and the dther adapted to slide upon the first member to permit said contraction.

9. The combination claimed in claim 8 provided with mechanical means for shitting the sliding members to allow the mold to be separated from the casting.

10. The combination claimed in claim 8 having a separate gate or pouring bar adapted to be removed after pouring and before the metal freezes. V

11. The combination claimed in claim 10, having said space having a thick cross section to act as a conduit for the flow of liquid metal through the mold.

12. A metal mold having a refractory lining composed of fire-proof bricks.

In testimony whereof, l have affixed my signature to this specification.

MYRON r. HILL. 

